Calibration fluid comprising pyrogallol for the calibration of blood gas, electrolyte, and/or metabolite instrument oxygen sensor(s)

ABSTRACT

Compositions, devices, kits, and methods for calibrating at least one oxygen sensor in a blood gas, electrolyte, and/or metabolite instrument utilizing a calibration fluid comprising a pyrogallol oxygen scavenger.

CROSS REFERENCE TO RELATED APPLICATIONS

Not Applicable. The subject application claims benefit under 35 USC §119(e) of U.S. provisional Application No. 62/529,525, filed Jul. 7,2017. The tire contents of the above-referenced patent application arehereby expressly incorporated herein by reference.

STATEMENT REGARDING FEDERALLY FUNDED RESEARCH OR DEVELOPMENT

Not Applicable.

TECHNICAL FIELD

The presently disclosed and claimed inventive concept(s) relate to acompositions(s), device(s), kit(s), and method(s) for calibrating atleast one oxygen sensor of a blood gas analyzer system. Morespecifically, the presently disclosed and claimed inventive concept(s)relate to a calibration fluid comprising pyrogallol for the calibrationof at least one oxygen sensor of a blood gas analyzer system.

BACKGROUND

Blood gas analyzers (“BGAs”) have been used for years in the medicalindustry to determine the presence and concentration of certain analyteswhich may be present in a patient's blood and/or blood sample. BGAs areroutinely used by doctors, scientists, researchers, and medical-careprofessionals to determine the presence and/or concentrations of certaincharacteristics and/or analytes present in a patient's blood sample,including, without limitation: (1) blood gases (such as pH (acidity),carbon dioxide (measured as pCO₂—partial pressure of carbon dioxide),and/or oxygen (measured as pO₂—partial pressure of oxygen)); (2)electrolytes (such as sodium (Na⁺), potassium (K⁺), Calcium (Ca²⁺),and/or chloride (Cl⁻)); (3) metabolites (such as glucose, lactate, bloodurea nitrogen (“BUN”), and/or creatinine); and/or co-oximetryconcentration measurements (such as total hemoglobin (tHb), reducedhemoglobin/deoxyhemoglobin (HHb), oxyhemoglobin (O₂Hb), saturated oxygen(sO₂), carboxyhemoglobin (COHb), methemoglobin (MetHb), fetal hemoglobin(HbF), and/or bilirubin.

When measuring the presence and/or concentration of oxygen present in apatient's blood sample, it is of utmost importance that the oxygensensor(s) of the blood gas analyzer be properly calibrated—an improperlycalibrated oxygen sensor(s) may miscalculate and incorrectly report theactual level(s) of oxygen that is/are present in a patient's bloodsample. Calibration of such oxygen sensor(s) (as well as other sensorspresent in the blood gas analyzer) is/are typically accomplished viaroutine calibration with at least one calibration fluid. The calibrationfluid(s) provide at least a floor measurement of oxygen (i.e., as closeto zero (0) millimeters of mercury (mmHg) as possible, with the goal ofthe floor being zero (0) mmHg) and a predetermined ceiling measurementof oxygen (for instance, by way of example only, 160 mmHg). By using atleast the floor and ceiling oxygen measurements, the blood gas analyzer,through algorithmic calculations and circuitry, calibrates the oxygensensor(s) of the blood gas analyzer to thereby allow for the accuratedetection of oxygen in a patient's blood gas sample.

To date, the calibration fluid most widely used to approximate the zero(0) mmHg floor oxygen measurement has been a calibration fluidcomprising a combination of sulfite and cobalt as oxygen scavengerreagents. While such oxygen scavenger reagents are effective in settingthe floor (i.e., zero (0) mmHg) oxygen measurement for the calibrationfluid, there are a number of disadvantages associated with using thesulfite/cobalt calibration fluid. First, cobalt is on the REACH list ofbanned and/or restricted substances in Europe due to its potential forcausing: (1) long-lasting and harmful environmental effects (especiallyto aquatic life); (2) cancer; and (3) fatalities, if inhaled. Inaddition, sulfite may have detrimental effects on the functioning ofother sensors of the blood gas analyzer (for example, a creatininesensor, due to the interactions between the sulfite and the creatininesensor).

In addition, maintaining oxygen levels within reagent bags utilized withBGAs and other types of instrumentation remains a well-known problem inthe art because of the oxygen permeability of most polymer-based reagentbag materials. Currently, the primary means to minimize such changes inoxygen levels of liquid reagents is to use a better oxygen barriermaterial and/or to keep the liquid reagents under low temperature toreduce the kinetic energy of oxygen. While oxygen scavengers have beenutilized to confront this problem, the primary sulfite and cobalt oxygenscavengers currently employed suffer from the drawbacks anddisadvantages stated herein above.

Accordingly, there is a need for an improved calibration fluid that isboth environmentally and medically safe, but which comprises an oxygenscavenging reagent(s), such as pyrogallol, that is effective in settingthe floor (i.e., as close to zero (0) mmHg as possible) oxygenmeasurement(s) of a calibration fluid for use in the calibration ofoxygen sensors present in a BGA. It is to such improved compositions,devices, kits, and methods that the presently disclosed and claimedinventive concept(s) is directed.

DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a graphical representation of a blood gas analyzer calibrationfluid comprising various percentages/concentrations of pyrogallol(x-axis) plotted against the partial pressures of oxygen (pO₂) producedwithin a zero-headspace pouch (measured in mmHg) for each particularpercentage/concentration of pyrogallol present within the calibrationfluid(s) (y-axis).

DETAILED DESCRIPTION

Before explaining at least one embodiment of the inventive concept(s) indetail by way of exemplary drawings, experimentation, results, andlaboratory procedures, it is to be understood that the inventiveconcept(s) is not limited in its application to the details ofconstruction and the arrangement of the components set forth in thefollowing description or illustrated in the drawings, experimentationand/or results. The inventive concept(s) is capable of other embodimentsor of being practiced or carried out in various ways. As such, thelanguage used herein is intended to be given the broadest possible scopeand meaning; and the embodiments are meant to be exemplary—notexhaustive. Also, it is to be understood that the phraseology andterminology employed herein is for the purpose of description and shouldnot be regarded as limiting.

Unless otherwise defined herein, scientific and technical terms used inconnection with the presently disclosed and claimed inventive concept(s)shall have the meanings that are commonly understood by those ofordinary skill in the art. Further, unless otherwise required bycontext, singular terms shall include pluralities and plural terms shallinclude the singular. The foregoing techniques and procedures aregenerally performed according to conventional methods well known in theart and as described in various general and more specific referencesthat are cited and discussed throughout the present specification. Thenomenclatures utilized in connection with, and the laboratory proceduresand techniques of, analytical chemistry, synthetic organic chemistry,and medicinal and pharmaceutical chemistry described herein are thosewell-known and commonly used in the art.

All patents, published patent applications, and non-patent publicationsmentioned in the specification are indicative of the level of skill ofthose skilled in the art to which this presently disclosed and claimedinventive concept(s) pertains. All patents, published patentapplications, and non-patent publications referenced in any portion ofthis application are herein expressly incorporated by reference in theirentirety to the same extent as if each individual patent or publicationwas specifically and individually indicated to be incorporated byreference.

All of the compositions, devices, kits, and/or methods disclosed andclaimed herein can be made and executed without undue experimentation inlight of the present disclosure. While the compositions and methods ofthis presently disclosed and claimed inventive concept(s) have beendescribed in terms of preferred embodiments, it will be apparent tothose of skill in the art that variations may be applied to thecompositions and/or methods and in the steps or in the sequence of stepsof the method described herein without departing from the concept,spirit and scope of the presently disclosed and claimed inventiveconcept(s). All such similar substitutes and modifications apparent tothose skilled in the art are deemed to be within the spirit, scope, andconcept of the inventive concept(s) as defined by the appended claims.

As utilized in accordance with the present disclosure, the followingterms, unless otherwise indicated, shall be understood to have thefollowing meanings:

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The singular forms “a,” “an,” and “the”include plural referents unless the context clearly indicates otherwise.Thus, for example, reference to “a compound” may refer to 1 or more, 2or more, 3 or more, 4 or more or greater numbers of compounds. The term“plurality” refers to “two or more.” The use of the term “or” in theclaims is used to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects. For example but not byway of limitation, when the term “about” is utilized, the designatedvalue may vary by ±20% or ±10%, or ±5%, or ±1%, or ±0.1% from thespecified value, as such variations are appropriate to perform thedisclosed methods and as understood by persons having ordinary skill inthe art. The use of the term “at least one” will be understood toinclude one as well as any quantity more than one, including but notlimited to, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 100, etc. The term “atleast one” may extend up to 100 or 1000 or more, depending on the termto which it is attached; in addition, the quantities of 100/1000 are notto be considered limiting, as higher limits may also producesatisfactory results. In addition, the use of the term “at least one ofX, Y and Z” will be understood to include X alone, Y alone, and Z alone,as well as any combination of X, Y and Z. The use of ordinal numberterminology (i.e., “first”, “second”, “third”, “fourth”, etc.) is solelyfor the purpose of differentiating between two or more items and is notmeant to imply any sequence or order or importance to one item overanother or any order of addition, for example.

As used in this specification and claim(s), the terms “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, un-recitedelements or method steps.

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof” is intended to includeat least one of: A, B, C, AB, AC, BC, or ABC, and if order is importantin a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, AAB, BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

The term “circuitry” as used herein includes, but is not limited to,analog and/or digital components, or one or more suitably programmedprocessors (e.g., microprocessors) and associated hardware and softwareor hardwired logic. The term “component” may include hardware, such asbut not limited to, a processors (e.g., microprocessor), an applicationspecific integrated circuit (ASIC), field programmable gate array(FPGA), a combination of hardware and software, and/or the like. Theterm “software” as used herein may include one or more computer readablemedium (i.e., computer readable instructions) that when executed by oneor more components cause the component to perform a specified function.It should be understood that the algorithms described herein may bestored on one or more non-transient memory. Non-limiting exemplarynon-transient memory may include random access memory, read only memory,flash memory, and/or the like. Such non-transient memory may beelectrically-based, optically-based, and/or the like.

As used herein, the term “substantially” means that the subsequentlydescribed event or circumstance completely occurs or that thesubsequently described event or circumstance occurs to a great extent ordegree. For example, the term “substantially” means that thesubsequently described event or circumstance occurs at least 90% of thetime, or at least 95% of the time, or at least 98% of the time.

As used herein, the term “pO₂” will be understood to refer to thepartial pressure of oxygen, that is, an amount of oxygen in a solution.“pO₂” may also be referred to as a level of oxygen dissolved in asolution.

As used herein, the terms “associate” or “associated with” includes bothdirect association of two moieties to one another as well as indirectassociation of two moieties to one another. Non-limiting examples ofassociations include covalent binding of one moiety to another moietyeither by a direct bond or through a spacer group, non-covalent bindingof one moiety to another moiety either directly or by means of specificbinding pair members bound to the moieties, incorporation of one moietyinto another moiety such as by dissolving one moiety in another moietyor by synthesis, and coating one moiety on another moiety.

The term “fluid sample” as used herein will be understood to include anytype of biological fluid sample that may be utilized in accordance withthe presently disclosed and claimed inventive concept(s). Examples ofbiological samples that may be utilized include, but are not limited to,whole blood or any portion thereof (i.e., plasma or serum), saliva,sputum, cerebrospinal fluid (CSF), intestinal fluid, intraperitonealfluid, pleural fluid, cystic fluid, sweat, interstitial fluid, tears,mucus, urine, bladder wash, semen, combinations, and the like. Thetypical liquid test sample utilized in accordance with the presentlydisclosed and/or claimed inventive concept(s) is blood. The volume ofthe fluid sample utilized in accordance with the presently disclosed andclaimed inventive concept(s) can be from about 0.1 to about 300microliters, or from about 0.5 to about 290 microliters, or from about 1microliter to about 280 microliters, or from about 2 microliters toabout 270 microliters, or from about 5 microliters to about 260microliters, or from about 10 to about 260 microliters, or from about 15microliters to about 250 microliters, or from about 20 microliters toabout 250 microliters, or from about 30 microliters to about 240microliters, or from about 40 microliters to about 230 microliters, orfrom about 50 microliters to about 220 microliters, or from about 60microliters to about 210 microliters, or from about 70 microliters toabout 200 microliters, or from about 80 microliters to about 190microliters, or from about 90 microliters to about 180 microliters, orfrom about 100 microliters to about 170 microliters, or from about 110microliters to about 160 microliters, or from about 120 microliters toabout 150 microliters, or from about 130 microliters to about 140microliters. In one non-limiting embodiment, the volume of the fluidsample is in a range of from about 100 microliters to about 200microliters.

The term “patient” includes human and veterinary subjects. In certainembodiments, a patient is a mammal. In certain other embodiments, thepatient is a human, including, but not limited to, infants, toddlers,children, young adults, adults, and elderly human populations. “Mammal”for purposes of treatment refers to any animal classified as a mammal,including human, domestic and farm animals, nonhuman primates, and zoo,sports, or pet animals, such as dogs, horses, cats, cows, etc.

Turning now to particular embodiments, the presently disclosed andclaimed inventive concept(s) relate to a composition(s), device(s),kit(s), and method(s) for calibrating at least one oxygen sensor of ablood gas analyzer system. While a patient's fluid sample is primarilydiscussed herein in the context of a patient's blood sample, it shouldbe readily understood by a person having ordinary skill in the art thatthe presently disclosed and/or claimed inventive concepts haveapplications to all types of a patient's fluid sample. Morespecifically, the presently disclosed and claimed inventive concept(s)relate to an improved calibration fluid comprising a predeterminedamount pyrogallol for the calibration of at least one oxygen sensor of ablood gas analyzer system, as well as devices, kits, and methods of userelated thereto.

The presently disclosed and/or claimed inventive concept(s) relate to amethod of generating desired oxygen levels for on-board calibration andquality control of at least one oxygen sensor (i.e., pO₂ sensor(s))within a sensor cartridge, including, without limitation, a single-useand/or multiple use sensor cartridge of a blood gas analyzer system. Inthe method, a calibration (and/or quality control) fluid comprises atleast one calibration and/or quality control reagent(s) and an aqueousor solid reagent containing an oxygen scavenger. The oxygen scavengerreduces the amount of dissolved oxygen in the calibration fluid througha chemical reaction in which the oxygen scavenger (i.e., reducing agent)is oxidized by oxygen; the chemical reaction is based on the reactionrate that is affected by the concentrations of the oxygen scavenger andoxygen, the temperature at which the reaction occurs, and the reactiontime. By controlling these parameters, the calibration fluid containingthe oxygen scavenger achieves the objectives of the presently disclosedand/or claimed inventive concepts, including, but not limited to,setting the floor measurement (i.e., as close to zero (0) mmHg aspossible) for the calibration of the at least one oxygen sensor presentwithin the sensor cartridge.

Next, an accurate concentration of the oxygen level in the calibrationand/or quality control reagent of the calibration fluid can becalculated. The sensor(s) utilized in accordance with the presentlydisclosed and/or claimed inventive concept(s) function via amperometryprinciples, meaning that the sensor(s) of the sensor array detect ionsgenerated in the calibration fluid in response to presence of theanalyte(s) of interest. Such ions, when in contact with the electrode(s)of the sensor array, generate an electric current or changes in electriccurrent (typically measured in amperes or nano amperes) which arereadily detected and measured by the electrode(s) of the sensor array.The current generated by the electrode(s) of the amperometric sensorarray is directly proportional to the concentration of the particularanalyte being tested, which, in one embodiment of the presentlydisclosed and/or claimed inventive concept(s), is oxygen. Amperometryand amperometric sensors are well known in the art and no furtherdiscussion is deemed necessary. When pyrogallol is used as the oxygenscavenger, pyrogallol chemically reduces the concentration of oxygen inthe calibration fluid (via pyrogallol complexing with the oxygen of thecalibration and/or quality control reagent(s)). As the concentration ofoxygen is reduced in the calibration fluid, the current measured by theelectrode(s) of the amperometric sensor array likewise decreases, thelevel of decrease being directly proportional to the concentration ofoxygen present in the calibration fluid. Accordingly, an accurateconcentration of oxygen present in the calibration fluid can then becalculated from the electrochemical current generated (as measured, forinstance, in nano amperes) between the amperometric sensor electrode andoxygen present in the calibration fluid (the concentration of oxygen inthe calibration fluid being directly proportional to the currentgenerated).

In a closed system, oxygen scavengers, such as pyrogallol, will bindoxygen present in the calibration fluid and lower the level of oxygenpresent within the calibration fluid. The oxygen level can varydepending on the concentration of oxygen scavenger present, the reactiontemperature, and the reaction time. In addition, prior to or after theaddition of the oxygen scavenger, the level of oxygen in the calibrationfluid can likewise be decreased by pumping out oxygen from the reagentreceptacle via a vacuum or via the addition of non-oxygen containinggas(es), including, without limitation, nitrogen and/or carbon dioxidegases.

Compositions utilized in accordance with the presently disclosed and/orclaimed inventive concept(s) include calibration and/or quality controlreagent(s) and oxygen scavenger-containing reagent(s). When thecalibration and/or quality control reagent is brought into contact withthe oxygen scavenger, the oxygen scavenger removes oxygen from thecalibration and/or quality control reagent(s) (and, as a result, thecalibration fluid), thereby providing a desired oxygen level (such as,by way of example only, zero (0) mmHg) in the calibration and/or qualitycontrol reagent(s) based on the concentrations of oxygen scavenger(s)and/or calibration/quality control reagent(s) present in the reaction aswell as the reaction time and/or temperature at which the reactionoccurs.

Any calibration and/or quality control reagent for use in thecalibration and/or monitoring of the performance of oxygen sensor(s) ofa blood gas analyzer system, such as, by way of example only,RAPIDPoint® 500 Blood Gas Systems commercially offered for sale bySiemens Healthcare Diagnostics, Inc., and for which a desired oxygenconcentration must be maintained is encompassed within the scope of thepresently disclosed and/or claimed inventive concept(s). In addition tothe calibration and/or quality control reagent(s), the calibration fluidmay further comprise any other component necessary for functionalitythereof, including, but not limited to, inorganic and/or organicsalt(s), protein(s), catalyst(s), analyte(s), metabolite(s), and/orgas(es). Such types of calibration and/or quality control reagent(s) arewell known in the art, and therefore no further discussion thereof isdeemed necessary.

Any oxygen scavenger known in the art and capable of functioning asdescribed or otherwise contemplated herein is encompassed within thescope of the presently disclosed and/or claimed inventive concept(s).Any reducing agent may function as an oxygen scavenger in accordancewith the presently disclosed and/or claimed inventive concept(s) as longas the reducing agent is capable of (i) removing dissolved oxygen froman aqueous solution/fluid (i.e., the calibration fluid) and (ii)generating an electrochemically active product capable of being measuredby amperometric sensor(s) (i.e., the electrode(s) of the amperometricsensor array of the presently disclosed and/or claimed inventiveconcept(s)). Examples of oxygen scavengers that may be utilized inaccordance with the presently disclosed and/or claimed inventiveconcept(s) include, but are not limited to, pyrogallol, as well as anycombination thereof. However, it should be readily understood to aperson having ordinary skill in the art that other oxygen scavengersthat are capable of functioning as described or other contemplatedherein are encompassed by the presently disclosed and/or claimedinventive concept(s), and, as such, no further discussion thereof isdeemed necessary. As discussed herein, in one non-limiting embodiment ofthe presently disclosed and/or claimed inventive concept(s), the oxygenscavenger is pyrogallol.

Any electrode known in the art and capable of functioning as describedor otherwise contemplated herein is encompassed within the scope of thepresently disclosed and/or claimed inventive concept(s). That is, anyelectrode may function as an electrode in accordance with the presentlydisclosed and/or claimed inventive concept(s) as long as the electrodeis electrochemically active and is capable of producing a current(s) inresponse to exposure to an analyte of interest (which is, in onenon-limiting embodiment of the presently disclosed and/or claimedinventive concept(s), oxygen) in a calibration fluid, the current(s)generated being directly proportional to the concentration of theanalyte of interest present in the calibration fluid. A non-limitingexample of an electrode that may be utilized in accordance with thepresently disclosed and/or claimed inventive concept(s) include a barmetal electrode. However, other electrodes that are capable offunctioning as described or otherwise contemplated herein after alsowell known in the art and encompassed by the presently disclosed and/orclaimed inventive concept(s), and, therefore, no further discussionthereof is deemed necessary.

Certain embodiments of the presently disclosed and/or claimed inventiveconcept(s) are directed to kits in which oxygen levels can be controlled(and/or specific oxygen levels can be generated) for calibration and/orquality control fluid(s); in addition, the generated desired oxygenlevels (for instance, a calibration fluid comprising an oxygenmeasurement of about zero (0) mmHg and an oxygen concentration of aboutzero (0)) can be accurately measured in the kits of these embodiments.The calibration and/or quality control fluid(s) may be used formonitoring the performance of, for example, but not by way oflimitation, blood gas (including pO₂ measurements of a patient's fluidsample), electrolyte, and/or metabolite instrumentation. The kitincludes at least one calibration and/or quality control fluid whichcomprises: (i) at least one calibration and/or quality control reagentcontaining oxygen, as described herein above or otherwise contemplatedherein; and (2) at least one second reagent that comprises at least oneoxygen scavenger. While the oxygen scavenger reagent is primarilydiscussed herein as being in an aqueous form, it should be readilyunderstood to a person having ordinary skill in the art that the oxygenscavenger-containing reagent may be in lyophilized or solidified form.When use of the calibration fluid is desired, a specific and/orpredetermined amount of the second reagent for instance, a pyrogalloloxygen scavenger reagent) is combined with the calibration and/orquality control reagent so that the oxygen scavenger complexes with andreduces the amount of oxygen present in the calibration and/or qualitycontrol reagent of the calibration fluid. In this manner, a desiredoxygen level can be provided in the calibration and/or quality controlfluid immediately before and/or at the time of use of the calibrationand/or quality control fluid. In one non-limiting embodiment, thepredetermined amount of the second reagent when combined with thecalibration and/or quality control reagent is such that the partialpressure of oxygen in the calibration and/or quality control fluid isabout zero (0) mmHg following the combination.

The oxygen scavenger may be used at a molar ratio of less than or equalto 1:1 with the oxygen of the calibration and/or quality control reagentof the calibration fluid. A person having ordinary skill in the artwould recognize that the resultant concentration of oxygen obtained inthe calibration fluids upon exposure of the calibration and/or qualitycontrol reagent(s) to the oxygen scavenger is directly related to: (i)the initial concentration of oxygen in the calibration and/or qualitycontrol reagent(s) of the calibration fluid; (ii) initial theconcentration of oxygen scavenger; (iii) the amount of time that theoxygen scavenger-containing reagent(s) is/are allowed to come intocontact with the calibration and/or quality control reagent; and/or (iv)the temperature at which the reaction occurs. For example, but not byway of limitation, it may be desired in the calibration fluid to utilizea molar ratio of oxygen scavenger:oxygen in the calibration/qualitycontrol reagent of about 0.001:1, about 0.002:1, about 0.003:1, about0.004:1, about 0.005:1, about 0.006:1, about 0.007:1, about 0.008:1,about 0.009:1, about 0.01:1, about 0.02:1, about 0.03:1, about 0.04:1,about 0.05:1, about 0.06:1, about 0.07:1, about 0.08:1, about 0.09:1,about 0.1:1, about 0.15:1, about 0.2:1, about 0.25:1, about 0.3:1, about0.35:1, about 0.4:1, about 0.45:1, about 0.5:1, about 0.55:1, about0.6:1, about 0.65:1, about 0.7:1, about 0.75:1, about 0.8:1, about0.85:1, about 0.9:1, about 0.95:1, and about 1:1. Alternatively, it maybe desired to utilize a molar ratio of oxygen scavenger:oxygen in thecalibration/quality control reagent in a range of any of the abovevalues (i.e., a range of from about 0.1:1 to about 1:1, or about 0.3:1to about 0.9:1, etc.), and therefore any range formed from thecombination of two values listed above is also encompassed within thescope of the presently disclosed and/or claimed inventive concept(s). Inone non-limiting embodiment, the concentration of the oxygen scavenger(such as, by way of example only, pyrogallol) in the calibration fluidis from about 0.05% to about 0.5%.

The reaction time may be any amount of time that allows for the oxygenscavenger-containing reagent to complex with oxygen in the calibrationand/or quality control reagent and that is suitable for use with themethods and devices disclosed or otherwise contemplated herein. Forexample, but not by way of limitation, the reaction time may be about0.001 second, about 0.002 second, about 0.003 second, about 0.004second, about 0.005 second, about 0.006 second, about 0.007 second,about 0.008 second, about 0.009 second, about 0.01 second, about 0.05second, about 0.1 second, about 0.15 second, about 0.2 second, about0.25 second, about 0.3 second, about 0.35 second, about 0.4 second,about 0.45 second, about 0.5 second, about 0.55 second, about 0.6second, about 0.65 second, about 0.7 second, about 0.75 second, about0.8 second, about 0.85 second, about 0.9 second, about 0.95 second,about 1 second, about 2 seconds, about 3 seconds, about 4 seconds, about5 seconds, about 6 seconds, about 7 seconds, about 8 seconds, about 9seconds, about 10 seconds, about 11 seconds, about 12 seconds, about 13seconds, about 14 seconds, about 15 seconds, about 16 seconds, about 17seconds, about 18 seconds, about 19 seconds, about 20 seconds, about 25seconds, about 30 seconds, about 35 seconds, about 40 seconds, about 45seconds, about 50 seconds, about 55 seconds, about 60 seconds, about 65seconds, about 70 seconds, about 75 seconds, about 80 seconds, about 85seconds, about 90 seconds, about 95 seconds, about 100 seconds, about105 seconds, about 110 seconds, about 115 seconds, about 2 minutes,about 3 minutes, about 4 minutes, about 5 minutes, about 6 minutes,about 7 minutes, about 8 minutes, about 9 minutes, about 10 minutes,about 11 minutes, about 12 minutes, about 13 minutes, about 14 minutes,about 15 minutes, about 16 minutes, about 17 minutes, about 18 minutes,about 19 minutes, about 20 minutes, about 25 minutes, about 30 minutes,about 35 minutes, about 40 minutes, about 45 minutes, about 50 minutes,about 55 minutes, about 60 minutes, and the like. Alternatively, it maybe desired to utilize a reaction time within a range of any of the abovevalues (i.e., a range of from about 0.01 second to about 20 minutes, orabout 1 second to about 10 seconds, etc.), and therefore any rangeformed from the combination of two values listed above is alsoencompassed within the scope of the presently disclosed and/or claimedinventive concept(s). In addition, in one non-limiting embodiment, theoxygen sensor(s) of the blood gas analyzer system is calibrated atintervals of time ranging from about 20 minutes to about 120 minutes. Inone non-limiting embodiment, the calibration of the at least one sensor(for instance, the at least one pO₂ sensor) occurs within 30 secondsfollowing the formation of the calibration fluid.

Any reaction temperature known in the art may be utilized in accordancewith the presently disclosed and/or claimed inventive concept(s) so longas the complexation of oxygen by the oxygen scavenger will occur at thattemperature, and as long as the temperature is suitable for use with themethods and devices disclosed or otherwise contemplated herein. Forexample, but not by way of limitation, the reaction temperature may beabout 0° C., about 1° C., about 2° C., about 3° C., about 4° C., about5° C., about 6° C., about 7° C., about 8° C., about 9° C., about 10° C.,about 11° C., about 12° C., about 13° C., about 14° C., about 15° C.,about 16° C., about 17° C., about 18° C., about 19° C., about 20° C.,about 21° C., about 22° C., about 23° C., about 24° C., about 25° C.,about 26° C., about 27° C., about 28° C., about 29° C., about 30° C.,about 31° C., about 32° C., about 33° C., about 34° C., about 35° C.,about 36° C., about 37° C., about 38° C., about 39° C., about 40° C.,about 41° C., about 42° C., about 43° C., about 44° C., about 45° C.,about 46° C., about 47° C., about 48° C., about 49° C., about 50° C.,and the like. Alternatively, it may be desired to utilize a reactiontemperature within a range of any of the above values (i.e., a range offrom about 4° C. to about 37° C., or about 20° C. to about 26° C.,etc.), and therefore any range formed from the combination of two valueslisted above is also encompassed within the scope of the presentlydisclosed and/or claimed inventive concept(s).

In certain embodiments, the calibration and/or quality controlreagent(s) and/or oxygen scavenger-containing reagent(s) comprising thecalibration fluid present in the kit may be aliquoted into single unitsthereof, or the kit may contain a volume of each reagent thatconstitutes multiple units thereof.

The calibration and/or quality control reagent(s) and/or oxygenscavenger-containing reagent(s) may be disposed in the kit in any formknown in the art that allows the reagents to function in accordance withthe presently disclosed and/or claimed inventive concept(s). Forexample, but not by way of limitation, the reagent(s) may be in aqueoussolution, lyophilized and/or solidified. When the reagent(s) arelyophilized and/or solidified, the reagents(s) may be disposed in thekit in any form, including, but not limited to, a bead, a hemisphere, acake, a tablet, or any other form, as well as any combination of theseor other types of forms. In addition, the calibration and/or qualitycontrol reagent and/or the oxygen scavenger-containing reagent may alsobe maintained in a substantially air tight environment until usethereof, including, without limitation, at least one air tight bag,container, bottle, ampule, and/or combinations thereof. In onenon-limiting embodiment, the calibration and/or quality control reagentand/or oxygen scavenger may be maintained and/or contained within an airtight, flexible package, such as the air tight, flexible packagedescribed and/or claimed in U.S. Pat. No. 5,780,302, the contents ofwhich is expressly incorporated in its entirety by reference.

The kit may further include a sensor array that includes at least oneelectrode capable of producing a current(s) in response to exposure toan analyte of interest (which is, in one non-limiting embodiment of thepresently disclosed and/or claimed inventive concept(s), oxygen) in acalibration fluid, the current(s) generated being directly proportionalto the concentration of the analyte of interest present in thecalibration fluid. In certain non-limiting embodiments, the sensor arraymay further comprise a pO₂ sensor(s) with which the calibration fluid isused.

Certain embodiments of the presently disclosed and/or claimed inventiveconcept(s) are also directed to methods of controlling an oxygen level(and/or generating a desired oxygen level, for instance, an oxygen levelof zero (0) mmHg) in a calibration fluid used in monitoring theperformance of, for example, blood gas, electrolyte, and/or metaboliteinstrumentation. In the method, the oxygen level of the calibrationfluid as described in detail herein above or otherwise contemplatedtherein is controlled by exposure to any of the oxygenscavenger-containing reagents described in detail herein above orotherwise contemplated herein, wherein the oxygen scavenger-containingreagent complexes with a specific amount of oxygen in the calibrationand/or quality control reagent(s) and thereby provides a desired levelof oxygen in the calibration fluid at the time of use. The calibrationfluid containing the desired oxygen level is then used to monitor theperformance of blood gas, electrolyte, and/or metaboliteinstrumentation, and the reagent contains a desired oxygen level (forinstance, by way of example only, an oxygen level of zero (0) mmHg)based upon the concentration of the oxygen scavenger and the reactiontime and reaction temperature of the exposure.

A person of ordinary skill in the art would recognize that the amount ofoxygen complexed by the oxygen scavenger is directly related to theamount of oxygen scavenger that is allowed to come into contact with thecalibration and/or quality control reagent as well as the time andtemperature at which the reaction occurs. The exposure is performed at aspecific reaction temperature and for a specific amount of time (asdescribed in detail herein above and/or otherwise contemplated herein)and may occur immediately prior to the use of the calibration fluid.

Certain embodiments of the method also include accurately measuring theoxygen level so generated. By way of example, and not by way oflimitation, when pyrogallol is used as the oxygen scavenger, pyrogallolchemically reduces the concentration of oxygen in the calibration fluid(via pyrogallol complexing with the oxygen of the calibration and/orquality control reagent(s)). As the concentration of oxygen is reducedin the calibration fluid, the current measured by the electrode(s) ofthe amperometric sensor array likewise decreases, the level of decreasebeing directly proportional to the concentration of oxygen present inthe calibration fluid. Accordingly, an accurate concentration of oxygenpresent in the calibration fluid can be calculated from theelectrochemical current(s) generated (as measured, for instance, in nanoamperes) between the amperometric oxygen sensor array electrode andoxygen present in the calibration fluid.

The presently disclosed and/or claimed inventive concept(s) isadditionally directed to a device capable of controlling an oxygen level(and/or generating different oxygen levels) in a calibration and/orquality control reagent for monitoring the performance of, for example,blood gas, electrolyte, and/or metabolite instrumentation; the devicemay also be capable of accurately measuring the oxygen level sogenerated. In certain non-limiting embodiments, the device is a sensorcartridge, such as but not limited to, a single-use sensor cartridgeand/or a multiple-use sensor cartridge. The device includes any of thecalibration and/or quality control reagents comprising oxygen describedin detail herein above, as well as any of the oxygenscavenger-containing reagents as described in detail herein above. Asdescribed in detail herein above, a person of ordinary skill in the artwould recognize that the amount of oxygen removed from the calibrationand/or quality control reagent is directly related to the amount ofoxygen scavenger that is allowed to come into contact with thecalibration and/or quality control reagent as well as the time andtemperature at which the reaction occurs.

The device may further include a sensor array, wherein the sensor arrayincludes a sensor (such as, but not limited to, a pO₂ sensor) and anelectrode. Once the desired oxygen level is generated, the oxygen levelso generated can be accurately measured using the electrode; forinstance, by way of example only, when pyrogallol is used as the oxygenscavenger, pyrogallol chemically reduces the concentration of oxygen inthe calibration fluid (via pyrogallol complexing with the oxygen of theof the calibration and/or quality control reagent(s)). As theconcentration of oxygen is reduced in the calibration fluid, the currentmeasured by the electrode(s) of the amperometric sensor array likewisedecreases, the level of decrease being directly proportional to theconcentration of oxygen present in the calibration fluid. Accordingly,an accurate concentration of oxygen present in the calibration fluid iscalculated from the electrochemical current generated (as measured, forinstance, in nano amperes) between the electrode(s) of the amperometricsensor array and oxygen present in the calibration fluid. Next, thecalibration fluid can be brought into contact with the sensor(s) of thesensor array, such as but not limited to a pO₂ sensor(s), thus allowingfor calibration of the sensor.

The presently disclosed and/or claimed inventive concept(s) is alsodirected to a method for monitoring the performance of blood gas,electrolyte, and/or metabolite instrumentation. In the method, any ofthe devices described herein above or otherwise contemplated herein isdisposed into a blood gas, electrolyte, and/or metaboliteinstrumentation, and the device is activated at a certain temperatureand for a certain period of time to provide a desired oxygen level forthe calibration and/or quality control reagent. The reagent containingthe desired oxygen level is then brought into contact with a pO₂ sensorfor calibration and/or quality control of the blood gas, electrolyte,and/or metabolite instrument. In one non-limiting embodiment, thedesired oxygen level is about zero (0) mmHg.

In certain embodiments of the method, the oxygen level generated in thecalibration and/or quality control reagent upon activation of the deviceis accurately measured. For instance, by way of example only, whenpyrogallol is used as the oxygen scavenger, pyrogallol chemicallyreduces the concentration of oxygen in the calibration fluid (viapyrogallol complexing with the oxygen of the of the calibration and/orquality control reagent(s)). As the concentration of oxygen is reducedin the calibration fluid, the current measured by the electrode(s) ofthe amperometric sensor array likewise decreases, the level of decreasebeing directly proportional to the concentration of oxygen present inthe calibration fluid. Accordingly, an accurate concentration of oxygenpresent in the calibration fluid is calculated from the electrochemicalcurrent generated (as measured, for instance, in nano amperes) betweenthe electrode(s) of the amperometric sensor array and oxygen present inthe calibration fluid.

The various embodiments of compositions, kits, devices, and methods ofthe presently disclosed and/or claimed inventive concept(s) may beutilized with any blood gas, electrolyte, and/or metabolite instrument(for instance, RAPIDPoint® 500 Blood Gas Systems commercially offered bySiemens Healthcare Diagnostics, Inc.) for which calibration and/orquality control is desired. In certain, non-limiting embodiments, theinstrument may be a point of care instrument. The blood gas,electrolyte, and/or metabolite instrument may be a system or systemsthat are able to embody and/or execute the logic of themethods/processes described herein. Logic embodied in the form ofsoftware instructions and/or firmware may be executed on any appropriatehardware. For example, logic embodied in the form of softwareinstructions and/or firmware may be executed by one or more componentson a dedicated system or systems, on a personal computer system, on adistributed processing computer system, and/or the like. In someembodiments, the entire logic may be implemented in a stand-aloneenvironment operating on an instrument (such as, but not limited to, apoint of care instrument). In other embodiments, the logic may beimplemented in a networked environment such as a distributed system inwhich multiple instruments collect data that is transmitted to acentralized computer system for analyzing the data and supplying theresults of the analysis to the instruments. Each element of theinstrument may be partially or completely network-based or cloud based,and may or may not be located in a single physical location.

Thus, in accordance with the presently disclosed and/or claimedinventive concept(s), there have been provided compositions, kits, anddevices, as well as methods of producing and using same, which fullysatisfy the objectives and advantages set forth hereinabove. Althoughthe inventive concept(s) has been described in conjunction with thespecific language set forth hereinabove, it is evident that manyalternatives, modifications, and variations will be apparent to thoseskilled in the art. Accordingly, it is intended to embrace all suchalternatives, modifications, and variations that fall within the spiritand broad scope of the presently disclosed and/or claimed inventiveconcept(s).

EXAMPLES OF USING CALIBRATION FLUIDS COMPRISING PYROGALLOL AS AN OXYGENSCAVENGER TO PRODUCE LOW OXYGEN CONCENTRATIONS IN BAGGED REAGENTS FORTHE CALIBRATION OF ON-BOARD OXYGEN SENSORS

Referring now to the Figure, and more particularly to FIG. 1, showntherein is a graphical representation of blood gas analyzer calibrationfluids comprising various percentages/concentrations of pyrogallol(x-axis) plotted against the partial pressures of oxygen (pO₂) producedwithin a zero-headspace pouch (measured in mmHg) for each particularpercentage/concentration of pyrogallol present within the calibrationfluid(s) (γ-axis). As shown in FIG. 1, the oxygen response is inverselyproportional to the amount of pyrogallol present within the calibrationfluid—that is, the higher the amount of pyrogallol in the calibrationfluid, the lower the partial pressure of oxygen of the calibration fluidwithin the zero headspace pouch.

As evidenced by FIG. 1, the partial pressure of oxygen measurements (inmmHg) indicates that increasing the percentage/concentration ofpyrogallol within the calibration fluid reduces the oxygen responseassociated with the calibration fluid. As the percentage/concentrationof pyrogallol is increased from 0.00% to 0.35% within the calibrationfluid, the partial pressure of oxygen associated with the calibrationfluid respectively decreases from about 27.5 mmHg within the zeroheadspace pouch to about 12.5 mmHg (thereby providing evidence regardingthe inverse relationship between the amount of pyrogallol oxygenscavenger within the calibration fluid and the partial pressure ofoxygen associated with the calibration fluid).

As discussed herein, the pyrogallol oxygen scavenger complexes with theoxygen present in the calibration and/or quality control reagent(s) tothereby reduce the levels of oxygen in the calibration fluid. As aresult of increasing the concentration of the pyrogallol oxygenscavenger, the level of oxygen response is reduced to about zero (0)nano amperes, which directly correlates to a concentration of oxygenpresent in the calibration fluid of about zero (0). As a result, thecalibration fluid is effective in setting the floor calibrationmeasurement (i.e., a concentration of oxygen of about zero (0) for theeffective calibration of at least one oxygen sensor present in a sensorarray of a blood gas, electrolyte, and/or metabolite instrument.Accordingly, the pyrogallol oxygen scavenger accomplishes the objectivesand advantages of the presently disclosed and/or claimed inventiveconcept(s).

NON-LIMITING EXAMPLES OF THE INVENTIVE CONCEPT(S)

A calibration fluid for calibrating at least one pO₂ sensor of a bloodgas, electrolyte, and/or metabolite instrument, comprising: at least onecalibration and/or quality control reagent comprising oxygen; and areagent comprising a pyrogallol oxygen scavenger, wherein a specificamount of the reagent comprising a pyrogallol oxygen scavenger iscombined with the at least one calibration and/or quality controlreagent comprising oxygen such that the pyrogallol oxygen scavengercomplexes oxygen present in the at least one calibration and/or qualitycontrol reagent comprising oxygen to provide a desired oxygenconcentration in the calibration fluid, and wherein the desired oxygenconcentration is measured via at least one electrode.

The calibration, wherein the at least one calibration and/or qualitycontrol reagent comprising oxygen and the reagent comprising apyrogallol oxygen scavenger are in aqueous solution.

The calibration fluid, wherein the at least one calibration and/orquality control reagent comprising oxygen and the reagent comprising apyrogallol oxygen scavenger are disposed in a substantially air tightenvironment until use thereof.

The calibration fluid, wherein the pyrogallol oxygen scavenger comprisesa concentration from about 0.05% to about 1% of the calibration fluid.

The calibration fluid, wherein the specific amount of the reagentcomprising a pyrogallol oxygen scavenger is from about 0.1 milliliter toabout 2 milliliters.

The calibration fluid, wherein the electrode is a bar metal electrode.

The calibration fluid, wherein the desired oxygen concentrationcomprises a partial pressure of oxygen of about zero millimeters ofmercury (mmHg).

A method of calibrating at least one pO₂ sensor of a blood gas,electrolyte, and/or metabolite instrument, the method comprising thesteps of: exposing at least one calibration and/or quality controlreagent comprising oxygen to a specific concentration of a reagentcomprising a pyrogallol oxygen scavenger to thereby form a calibrationfluid, such exposure occurring immediately prior to the use of thecalibration fluid, wherein the exposure is performed at a specificreaction temperature and for a specific amount of time, whereby thecalibration fluid is thereby provided with a desired oxygenconcentration based upon the concentration of the pyrogallol oxygenscavenger and the time and temperature of the exposure, and wherein thedesired oxygen concentration is measured via at least one electrode of asensor array, the senor array comprising the at least one electrode andat least one pO₂ sensor; and; contacting the calibration fluid havingthe desired oxygen concentration with the at least one pO₂ sensor of thesensor array.

The method, wherein the at least one calibration and/or quality controlreagent comprising oxygen and the reagent comprising a pyrogallol oxygenscavenger are in aqueous solution.

The method, wherein the at least one calibration and/or quality controlreagent comprising oxygen and the reagent comprising a pyrogallol oxygenscavenger are disposed in a substantially air tight environment untiluse thereof.

The method, wherein the pyrogallol oxygen scavenger comprises from about0.05% to about 1% of the calibration fluid.

The method, wherein the specific reaction temperature if from about 20°C. to about 26° C.

The method, wherein the specific reaction time is from about 0.01 secondto about 60 seconds.

The method, wherein the desired oxygen concentration comprises a partialpressure of oxygen of about zero millimeters of mercury (mmHg).

A kit for calibrating at least one pO₂ sensor of a blood gas,electrolyte, and/or metabolite instrument, the kit comprising: acalibration fluid, comprising: at least one calibration and/or qualitycontrol reagent comprising oxygen; and a reagent comprising a pyrogalloloxygen scavenger; and a sensor array comprising at least one electrodecapable of measuring a desired concentration of oxygen in thecalibration fluid, wherein, when calibration of the at least one pO₂sensor is desired, a specific amount of the reagent comprising apyrogallol scavenger is combined with the at least one calibrationand/or quality control reagent comprising oxygen such that thepyrogallol oxygen scavenger complexes oxygen present in the at least onecalibration and/or quality control reagent to provide the desired oxygenconcentration in the calibration fluid, and wherein the desired oxygenconcentration is measured via the at least one electrode of the sensorarray prior to contacting the at least pO₂ sensor with the calibrationfluid for calibration thereof.

The kit, wherein the at least one calibration and/or quality controlreagent comprising oxygen and the reagent comprising a pyrogallol oxygenscavenger are in aqueous solution.

The kit, wherein the at least one calibration and/or quality controlreagent comprising oxygen and the reagent comprising a pyrogallol oxygenscavenger are disposed in a substantially air tight environment untiluse thereof.

The kit, wherein the pyrogallol comprises a concentration from about0.05% to about 1% of the calibration fluid.

The kit, wherein the specific amount of the reagent comprising apyrogallol oxygen scavenger is from about 0.1 milliliter to about 2milliliters.

The kit, wherein the electrode is a bar metal electrode.

The kit, wherein the desired oxygen concentration comprises a partialpressure of oxygen of about zero millimeters of mercury (mmHg).

Thus, in accordance with the presently disclosed and claimed inventiveconcept(s), there have been provided devices, kits, and methods fordetecting at least one analyte present in a patient's low-volume liquidtest sample. As described herein, the presently disclosed and claimedinventive concept(s) relate to embodiments of improved low-sample volumeurinalysis assay strips for use in analyte(s) detection assay, as wellas kits and methods of use related thereto. Such presently disclosedand/or claimed inventive concept(s) fully satisfy the objectives andadvantages set forth hereinabove. Although the presently disclosed andclaimed inventive concept(s) has been described in conjunction with thespecific drawings, experimentation, results and language set forthhereinabove, it is evident that many alternatives, modifications, andvariations will be apparent to those skilled in the art. Accordingly, itis intended to embrace all such alternatives, modifications andvariations that fall within the spirit and broad scope of the presentlydisclosed and claimed inventive concept(s).

What is claimed is:
 1. A calibration fluid for calibrating at least onepO₂ sensor of a blood gas, electrolyte, and/or metabolite instrument,comprising: at least one calibration and/or quality control reagentcomprising oxygen; and a reagent comprising a pyrogallol oxygenscavenger, wherein a specific amount of the reagent comprising apyrogallol oxygen scavenger is combined with the at least onecalibration and/or quality control reagent comprising oxygen such thatthe pyrogallol oxygen scavenger complexes oxygen present in the at leastone calibration and/or quality control reagent comprising oxygen toprovide a desired oxygen concentration in the calibration fluid, andwherein the desired oxygen concentration is measured via at least oneelectrode, wherein the at least one calibration and/or quality controlreagent comprising oxygen and the reagent comprising a pyrogallol oxygenscavenger are in aqueous solution, wherein the at least one calibrationand/or quality control reagent comprising oxygen and the reagentcomprising a pyrogallol oxygen scavenger are disposed in a substantiallyair tight environment until use thereof.
 2. The calibration fluid ofclaim 1, wherein the pyrogallol oxygen scavenger comprises aconcentration from about 0.05% to about 1% of the calibration fluid. 3.The calibration fluid of claim 1, wherein the specific amount of thereagent comprising a pyrogallol oxygen scavenger is from about 0.1milliliter to about 2 milliliters.
 4. The calibration fluid of claim 1,wherein the electrode is a bar metal electrode.
 5. The calibration fluidof claim 1, wherein the desired oxygen concentration comprises a partialpressure of oxygen of about zero millimeters of mercury (mmHg).
 6. Amethod of calibrating at least one pO₂ sensor of a blood gas,electrolyte, and/or metabolite instrument, the method comprising thesteps of: exposing at least one calibration and/or quality controlreagent comprising oxygen to a specific concentration of a reagentcomprising a pyrogallol oxygen scavenger to thereby form a calibrationfluid, such exposure occurring immediately prior to the use of thecalibration fluid, wherein the exposure is performed at a specificreaction temperature and for a specific amount of time, whereby thecalibration fluid is thereby provided with a desired oxygenconcentration based upon the concentration of the pyrogallol oxygenscavenger and the time and temperature of the exposure, and wherein thedesired oxygen concentration is measured via at least one electrode of asensor array, the sensor array comprising the at least one electrode andat least one pO₂ sensor; and contacting the calibration fluid having thedesired oxygen concentration with the at least one pO₂ sensor of thesensor array for calibration of the at least one pO₂ sensor, wherein theat least one calibration and/or quality control reagent comprisingoxygen and the reagent comprising a pyrogallol oxygen scavenger are inaqueous solution, wherein the at least one calibration and/or qualitycontrol reagent comprising oxygen and the reagent comprising apyrogallol oxygen scavenger are disposed in a substantially air tightenvironment until use thereof.
 7. The method of claim 6, wherein thepyrogallol oxygen scavenger comprises from about 0.05% to about 1% ofthe calibration fluid.
 8. The method of claim 6, wherein the specificreaction temperature if from about 20° C. to about 26° C.
 9. The methodof claim 6, wherein the specific reaction time is from about 0.01 secondto about 60 seconds.
 10. The method of claim 6, wherein the desiredoxygen concentration comprises a partial pressure of oxygen of aboutzero millimeters of mercury (mmHg).
 11. A kit for calibrating at leastone pO₂ sensor of a blood gas, electrolyte, and/or metaboliteinstrument, the kit comprising: a calibration fluid, comprising: atleast one calibration and/or quality control reagent comprising oxygen;and a reagent comprising a pyrogallol oxygen scavenger; and a sensorarray comprising at least one electrode capable of measuring a desiredconcentration of oxygen in the calibration fluid, wherein, whencalibration of the at least one pO₂ sensor is desired, a specific amountof the reagent comprising a pyrogallol scavenger is combined with the atleast one calibration and/or quality control reagent comprising oxygensuch that the pyrogallol oxygen scavenger complexes oxygen present inthe at least one calibration and/or quality control reagent to provide adesired oxygen concentration in the calibration fluid, and wherein thedesired oxygen concentration is measured using the at least oneelectrode of the sensor array prior to contacting the at least pO₂sensor with the calibration fluid for calibration thereof, wherein theat least one calibration and/or quality control reagent comprisingoxygen and the reagent comprising a pyrogallol oxygen scavenger are inaqueous solution, wherein the at least one calibration and/or qualitycontrol reagent comprising oxygen and the reagent comprising apyrogallol oxygen scavenger are disposed in a substantially air tightenvironment until use thereof.
 12. The kit of claim 11, wherein thepyrogallol comprises a concentration from about 0.05% to about 1% of thecalibration fluid.
 13. The kit of claim 11, wherein the specific amountof the reagent comprising a pyrogallol oxygen scavenger is from about0.1 milliliter to about 2 milliliters.
 14. The kit of claim 11, whereinthe electrode is a bar metal electrode.
 15. The kit of claim 11, whereinthe desired oxygen concentration comprises a partial pressure of oxygenof about zero millimeters of mercury (mmHg).